Question

A man standing in front of a vertical cliff fires a gun and hears the echo after $2$ seconds. Find the distance of the cliff from his position. (Assume velocity of sound is $360m/s$)

• A. 7500 m
• B. 750 m
• C. 550 m
• D. 5500 m

Answer 1

The correct option is B

750 m

Let the distance of the cliff be $dmeters$.

Since echo is a reflection of the original sound, it will travel distance equal to twice the distance between man and cliff i.e., $2d$.

The velocity of sound $v$ = $360m/s$)
Time taken for sound to travel = $2s$

We know that velocity is the ratio of distance and time take to cover the distance.

Here, $v=\frac{2d}{t}\Rightarrow d=\frac{v\times t}{2}$

$d=\frac{360\times 2}{2}=360m$